Half Lives

On this day, September 28, 2015, slightly before noon, American Central Time, in Mrs. Frankenberg's chemistry classroom at Francis Howell High School in the city of St. Charles, Missouri, in the United States of America, a number of students were given instruction upon how to calculate the amount of a radioactive isotope that remains radioactive after a given period of time. To do that, one must divide the original amount of isotope by two to the power of n, n being the number of half lives in the given amount of time. The formula is provided in the below image. Further clarification about half lives is supplied on AUS-e-TUTE's website.

http://www.coolmath.com/algebra/17-exponentials-logarithms/13-radioactive-decay-decibel-levels-01